Fans



June 28, 1960 B. ECK 2,942,77

Filed March 1, 1955 4 Sheets-Sheet 1 IN V EN TOR.

fi-Mml f JM June 28, 1960 c 2,942,773

FANS

Filed March 1, 1955 4 Sheets-Sheet 2 IN VE R. flaw A June 28, 1960 Filed March 1, 1955 4 Sheets-Sheet 3 INVENTOR. fimw hf BY M f. fr%c/ B. ECK

Jlme 28, 1960 FANS 4 Sheets-Sheet 4 Filed March 1, 1955 INVENTOR. fl/uwa 4% United States Patent FANS Bruno Eek, Koln-Klettenberg; Germany, assignor to Paul Pollrich & Comp., Munich-Gladbach, Germany, a firm Filed Mar. 1, 1955, Ser. No. 493,432v

In Germany July 17, 1953* Public Law 619, Aug. 23, 1954 Patent expires .Iuly 17, 1973 14- Claims. (Cl. 230-125) The present invention relates to fans:

In general there are two classical typesof well known fans, namely, the axial flow type of'fan andjthe radial flow type offfan. Both of these known types of fans have disadvantages. Thus, these known'fans invariably make a great amount of noise during theiroperation, and considerable problems are involved in locating such fans in small spaces. placing one of these known fans'to provide great variations inthe output.

One of the objects of the present'invention'is to overcome the above drawbacks by providing'a fan which will operatewith far less noise than'the above-discussed conventional fans, will provide a higher output than.v the known fans for a given size and' speed of'rotation ofthe fans, and will be capable of providing a wide range in Furthermore, it is difiicult without rel output simply by changing the speed of rotation of the fan.

Another object of the present inventionis to provide a fan which, except for the motor which drives the same, may be entirely located within a duct so that a minimum of space is required for the fan of the invention. I A further object of the present invention is to provide an arrangement according to which almost any desired number of fans may be connected to the same source of energy to be driven thereby. I

An additional object of the present invention is to provide a fan construction which may be very easily adapted to any given conditions.

Also, the objects of the present invention includesthe provision of a fan which may be constructedfofwell known materials and with the same tools. as are. used for the construction of conventional fans.

With the above objects in. view the present invention mainly consists of a fan which includes a plurality of elongated impeller blades of'substantially the samelength uniformly distributed about, a cylindrical space and respectively having inner side edges. located along a. first cylinder and outer side, edges locatedalong a second. cylinder coaxial with and greater than thefirst. cylinder, these blades being substantially parallel to the common axisof the cylinders. A casing means. supports thev impeller means for rotation, about this. common axis, and this casing means is formed with an inlet. communicating at any given instant with afirst; plurality of blades, located onv one side of the abovefmentioned axis. and withan outlet communicating at any given instant witha second plurality. of, blades locatedat. an. opposite. side; of. this axis, thecasingmeans alsoincluding a first. arcuate wall portion extending fromgthe inlet to the. outlet and. located closely adjacent to-andconforminstothe curvature. of the above-mentioned" second cylinder. and asecond arcuate wall portion opposite, this firstwall portion, also extending; from. the. inlet, tothe, outlet of: the-casing: means,v and having end; portions. respectively: located: adjacent: the inlet and outletwith the 1 end portion. adjacentqthe. inlet' located 'nearerto the. abovementioned axis. then the endz portion 2,942,173 Patented June 28, 1960 adjacent the outlet, sothat this second wall portion of the casing forms with'the above-mentioned second cylinder 3 gap which. converges from saidinlet toward'said outlet.

The novel features which. are considered as characteristic for the invention. are set forth in particular in the appendedclaims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantage thereof, will be bestunderstoodfrom the following description of specific embodiments when read in. connection with the accom, panying drawings, in which:

Fig. l'is a sectional side elevational view of a fan constructed in accordance with the present invention;

Fig; 2 isa fragmentary view corresponding to Fig. 1 of part of the fan of Fig. 1 with. a different structure located within the fan;

Fig. 3 is. a fragmentary sectional view taken along the line 3--3 of .Fig. l in the direction. of the arrows;

Fig. 4 is a side sectional view taken along the line 4-4 ofv Fig. 5 in the direction of the arrowsof another fan constructed in accordance with the present invention, Fig. 4 showing the dimensional relationships between the parts of the fan ofthe present invention;

Fig. 5 is a plan view of the fanof Fig. 4;.

Fig. 6 is-a sectional view taken along the line 6-6 of. Fig. 5 inthe direction of the arrows;

Fig.- 7 is aschematicside view of another .form of fan constructedin accordance with the present invention;

Fig. 8-. is an end view of. the fan of Fig. 7 as seen from the left side of. Fig. 7;

Fig. 9-is atop plan view-of the-fan of. Fig. 7; v

Fig. 10 is a schematic side view of still another form offan constructed in accordance with the present invention;

Fig. 11 isia schematic side elevational view of afurther. form of. a fan constructedin accordance'with the present invention; and

Fig. 12. shows ina schematic side elevational view a still, further embodiment of the present invention.

Before proceeding to a detailed. discussionof the drawings shown in this application, it is pointed out that the fan of the. present invention differs basically from known fans in that it cannotbe classifiedeither as a radial flow fan. or: asan axial. flow fan. According to the present inventionair is'sucked into the fan of the: invention through. the spaces between some of the impeller blades ofthe fan andthisair (or other fluid) passes across the interior of the fan and moves out: through the spaces between some of the impeller blades, at a particular instant. Thus, with .the fan of the presentinventionthe fluidflows twice through the. bladesof the. impeller.

Referring. now' to the drawings, Fig. 1. shows an impeller 1 provided with impeller blades distributed along acylinder, as is. evident from. Fig; 1, the impeller 1 turning in. a clockwise. direction, as. viewed in Fig. l, and as. indicated by the arrow of Fig. 1. ,The' impeller blades of. the impeller Late located about a. cylindrical space 2 within which. guides 3 and 4 for the air are located. The impeller is supportedfor' rotation. by a casing which is formed withaan. inlet. 5 and an outlet 6, and it will be: noted that the inlet: angleextending from point'7 to point. Sindicatedin. Fig. 1'. is greater than the outlet angle. extending; from. point? 9' to point 10 indicated in Fig. 1 Fig. 3 shows-themannerin-whichtheimpeller and guides .3- and 4 are mounted on the. casing; 1-5.- Thus, this'casing 1-5 includes-side Walls 16- and. 17, and. the guides 3 and 4,;as well as the. several guides shown in Fig. 1. betweentthe. guides-3 and 4 extendv between. and arev fixedzto a pair. of; end plates 1-8 and 19;v The end platev 18- is. fixed. to a pair; of studs 20: which; extend to andarerfixed to the side wall. 17,1and1-the end. plate 19 is located within the impeller 1. This impeller 1 is coaxial with the cylinder in which the guides are located, and the blades of the impeller are carried by a pair of rings 21 and 222 which areslidable on the peripheriesof the end plates 19 and 18, respectively, so that these end plates form bearings for the impeller. The ring 21 is in the form of an annular flange integral with a plate 23 fixed .to a shaft 24 which extends through side wall 16 of the casing 15 and which is turnably supported by the side wall, a pulley 25 or the like being fixed to the shaft 24 so that in this way impeller 1 may be driven.

In operation, as the impeller 1 turns in a clockwise direction, as viewed in Fig. 1, the blades of the impeller suck air in through the inlet '5, force this air along the space 2 where the guides for the air are located, and the air is forced again through the impeller blades out through the outlet 6. It will be noted that the angle of the inlet about the axis of rotation of the impeller is greater thanthat of the outlet 6.

Fig. 2. shows a fan identical with that of Fig. 1 except that the interior of the space surrounded by the impeller is provided, in addition to the guide 3, with a single guide and a plurality of stationary vanes 11, as indicated in Fig. '2, the guides of Fig. 2 operating in the same way as the guides of Fig. 1 to direct the air across the space surrounded by the impeller.

Figs. 4-6 show a preferred construction of a fan in accordance with the present invention. Thus, referring to Figs. 4-6 it will be seen that the fan disclosed therein includes a casing 30 in which the impeller 31 is supported for'rotation. As may be seen from Fig. 6, the impeller 31 is carried for rotation by the side walls 32 of the casing 30. The impeller includes a pair of circular, coaxial, end plates 33 each of which is fixed to a shaft 34 extending outwardly through an opening in a side wall 32 to be turnably supported by the casing 30. The

right shaft 34 of Fig. 6 is fixed to a pulley 35 so that with abelt a drive may be transmitted from any suitable motor or the like to the impeller. The blades 36 are located between and fixed to the end plates 33, and it will be noted that with the fan of Figs. 4-6 there is absolutely nothing in the space surrounded bythe impeller. It will be noted from Figs. 5 and 6 that the impeller is quite long, and in fact it is possible to make the impeller blades of any desired length without in any way altering the operation of the fan of the invention.

As may be seen from Fig. 4, the casing 30 is provided with an inlet 37 which converges as it approaches the impeller 31 and with an outlet 38 which diverges as it leaves the impeller 31. Furthermore, it'will be noted that, as was the case with the embodiment of Fig. l, the angle through which the inlet 37 extends about the axis 39 of the impeller is larger than the angle through which the outlet 38 extends about this axis. The inlet and outlet ducts each communicates with the rotor at the periphery thereof over an angle of at least 90, as is evident from Fig. 4.

It has been found empirically that in order 'to produce the best possible results it is necessary for the elements of the fan of the invention to have certain relationships with respect to each other, and such relationships are indicated in Fig. 4. Fig. 4 showsa fan where the outlet 38 extends in general along a direction, taken at random, parallel to the plane 40 passing through the axis of the impeller, and the inlet 37 extends in a direction parallel to the horizontal plane 41 shown in Fig. 4. In order to show the relationship between the several ele ments of the fan of the invention, it is assumed that'thc cylinder along which the inner side edges of the blades 42 of the impeller are located has a radius of 1. With such a radius of 1 for this inner cylinder, the outer cylinder along which the outer side edges of the blade 42 are located, will have a radius of approximately 1.25. Furthermore, each of the blades 42 itself forms part of a cylinder. It is preferred to provide 36 blades on the impeller so that the blades are spaced from each other by 10, and the cylinder of which each blade forms a part has a radius 43 which is approximately as long as the distance between each pair of adjacent blades, the center of radius 43 being located between the inner and outer cylinders 44 and 45 in which the inner side edges and outer side edges of the blade 42 are respectively located. The center of the radius 43 may be located mid= way between cylinders 44 and 45 at a distance of 1.125 from the axis 39.

The inner edge of each blade 42 is curved in the direction of rotation of the impeller.

On the other hand, the outer side edge of each blade 3 42 may make an angle of between 25 and 40 with a tangent to the cylinder 45, as shown in Fig. 4. Thus, it has been found by test that the particular angle made by the outer side edge of each blade with the outer cylinder 45 is not particularly critical as long as it is somewherebetween 25 and 40. Thus, actual fans constructed in accordance with the present invention and operating very successfully have had angles at the outer side edges of the blades, respectively with the cylinder 45 of 26 and also of 38. However, the angle of the inner side edge of each blade with a tangentto the cylinder 44 is always 70' or very close thereto.

The casing 30 includes a wall portion 46 extending from the inlet to the outlet and an opposite wall portion 48 extending from the inlet to the outlet. As is evident from Fig. 4, the wall portion 46 is located closely adjacent to and corresponds closely to the curvature of the cylinder. 45. It has been found best to terminate the wall portion 46 at its inlet end at a distance of 0.9 from the plane 40, as indicated in Fig. 4, and the wall portion 46 merges beyond this point with the part of the casing 30 which forms the inlet 37. The opposite end of the wall portion 46 is preferably formed along a curve having aradius of approximately 2.4, the center of this radius being located at a distance of approximately 0.9 from plane 47 which is normal to the plane 40 and at a distance of-0.5 from the plane 40, as shown in Fig. 4. Furthermore, it will be noted that the top wall of the outlet 38, as viewed in Fig. 4, is located in a plane which is perpendicular to the axis 47.

7 A particular feature of the invention resides in the configuration of the wall 48 of the casing 30. This wall 48has a radius of curvature slightly less than 1, such as, for example, 0.9. Furthermore, this radius has its center spaced by 0.2 from plane 40 and 0.6 from plane 47, as shown in Fig. 4. It will be noted that wall portion 48 thus has its end portion next to the inlet 37 located nearer to the axis 39 than its end portion next to the outlet 38, and as a result the wall portion 48 forms with a cylinder 45 a gap which converges as it approaches the inlet 37. At the point where the wall portion 48 is located furthest from the axis 39 it extends toward the outlet 38 along a tangent to this point so that this tangential part of wall portion 48 makes an angle of with the radius of curvature of wall portion 48 at this point furthest from the axle 39.

As a result of this latter feature of the invention, the impeller 31 when driven in a clockwise direction, as viewed in Fig. 4, creates a whirling body of air 49 indicated in dot-dash lines in Fig. 4. This whirling body of air acts in the same way as a solid guide of thetype shown in Figs. 1 and 2 so that it is possible to eliminate such solid guides with the construction shown in Fig. 4. The whirling body of air 49 which moves continuously in a clockwise direction, as the impeller itself rotates in a clockwise direction, does not in any way interfere with the air passing through the fan and serves to guide this air in the same way as the solid guide would.

It is pointed out that no units are given for the above discussed relationships since the particular size of the fan is a matter of choice. In other words, the radius of the inner cylinder 44 may be 1', or 6", or 2', or any other desired dim'ension depending upon the conditions tobe met by thefarn- It-is-on1yimportanf that the several parts of the fan have the relationshipsindicated in'Fig. 4 and described above, and evenhereall' of these relationships are approximate. Furthermore,theradius-of curvature of the wall portion 48 should be' -equal to the dist-ance between the plane 47 and-the'center of the. radius of curvature of the-endportiomof wan: 30 next td the outlet 38.

The structure of the present invention may take many different forms. Thus; Figs;-'7--9 af respectiVely side, end, and top plan views of a fan constructed in accordance with f'the'present' inventionand""having its housing 302': 'shaped' so" as to direct"air"after passing thfo'ughjthe fan in'a direction'which'rnakes' an' ang'lof 90*Witlf'the air entering the fan. Figs. 7-9 further show diagrammatically the motor 15 which drives the impeller through the belt 51. Any suitable means may be provided to adjust the tension of the belt 51. As is indicated in dotted lines in Fig. 7, the walls of the casing 30 which are next to the impeller conform to the above requirements.

Fig. 10 shows an arrangement where the casing 30!) is shaped so as to direct the air issuing from the fan at an angle of 45 with the air entering the fan. Fig. 11 shows an arrangement where the casing 300 is shaped to direct the air leaving the fan in a direction which makes an angle of 0 with the air entering the fan, and Fig. 12 shows an arrangement similar to that of Figs. 7-9 in that the air is deflected through 90 by the casing 30d after passing through the fan. However, it will be noted that the air enters and leaves the casing 30d at an angle of 45 with respect to a horizontal plane.

As is shown in the dotted lines of Figs. 10-12, the walls of the casings 30b, 30c and 30d, where they are located next to the impeller conform closely to the requirements discussed above in connection with Fig. 4.

It has been found that with the fan of the invention, which may be called a cross flow fan, produces far less noise at a given speed of rotation than either a radial oraxial flow conventional fan operating at the same speed of rotation. Furthermore, it will be noted that the fan of the invention may have its impeller located directly within a duct, so that very little space is required for the fan of the invention. The impeller may be made of any desired length, since the length of the impeller in no way influences the operation of the fan of the invention. In order to vary the output of the fan of the invention, it is only necessary to change the speed of rotation of the impeller accordingly. Furthermore, with the fan of the invention there are no operating characteristics which change suddenly at two speeds of operation which are close to each other. In other words, when increasing or decreasing the speed of rotation of the fan of the invention there is no danger of passing through certain critical speeds as is the case with known fans.

While the invention has been illustrated and described as embodied in cross flow fans, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications Without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A fan comprising, in combination, impeller means having a predetermined direction of rotation including a plurality of elongated impeller blades of substantially the same length uniformly distributed about a cylindrical space and respectively having inner side edges located alonga first cylinder 'andfouter 'side edgeslocated along a second cylinder coaxial with and reatc'r thansaidfirst' cylinder, said "blades being substantiallyparallehto' the common axis of said cylinders, and a casing supporting said impeller means for rot'atit'in about-said axis; said casing having-an inlet communicating at any given inst'a'nt'with" a first plurality of blades-located on one side of said axis and with an outlet-coin.rntinicating*atany givcn 'instant-withasecond pluralit'y'of blades" located at 'anopposite side "of said axis and said casing 1 including a first arcuate wall portion extendingfron'i said inlet-to said outlet in the predetermined direction of rotation'of the impellenand located closely adjacent to and conforming to the curvature ofsaid seedr'id cylinder, and a second arcuate-wall; portion opposite said first wall portion-also extending from said inlet to said outlet in a direction'opposite to that of said predetermined direction of rotation of the impeller and spaced throughout its length from the curvature of the second cylinder by a distance substantially greater than the distance between the first wall portion and the second cylinder, and having end portions respectively located adjacent said inlet and outlet with said end portion adjacent said inlet located nearer to said axis than said end portion adjacent said outlet, so that said second wall portion forms with said second cylinder a gap which converges from said outlet toward said inlet in the predetermined direction of rotation of said impeller, whereby a part of the fiuid flowing from the inlet to the outlet is reversed and flows backward into said gap and then through the blades into the interior of the cylindrical space.

2. In a fan as claimed in claim 1, each of said blades having, when located adjacent said gap, a concave face directed toward said inlet.

3. In a fan as claimed in claim 1, each of said blades having, when located adjacent said gap, a concave face directed toward said inlet and a convex face directed toward said outlet.

4. In a fan as claimed in claim 1, said inlet and outlet each having a rectangular cross section, each extending about said axis through an angle of more than and the angle through which said inlet extends about said axis being greater than that through which said outlet extends about said axis.

5. In a fan as claimed in claim 1, the outer portion of each blade making with a tangent to said second cylinder an angle of between 25 and 45.

6. In a fan as claimed in claim 1, said second cylinder having a radius approximately 1.25 times that of said first cylinder.

7. In a fan as claimed in claim 1, each blade itself forming a part of a cylinder.

8. In a fan as claimed in claim 1, each blade itself forming a part of a cylinder having an axis located between said first and second cylinders and adjacent the next blade.

9. In a fan as claimed in claim 1, said second wall portion having a radius of curvature slightly less than the radius of said first cylinder.

10. In a fan as claimed in claim 1, each blade itself forming part of a cylinder having an axis located between said first and second cylinders and adjacent the next blade, said blades each making with a tangent to said second cylinder an angle of between 25 and 40, and said second cylinder having a radius approximately 1.25 times that of said first cylinder, said inlet and outlet each having a rectangular cross section, each extending about said axis through an angle of more than 90, and the angle through which said inlet extends about said axis being greater than that through which said outlet extends about said axis, said second wall portion having a radius of curvature slightly smaller than the radius of said first cylinder, and each of said blades having, when it is located adjacent said gap, a concave face directed toward said inlet and a convex face directed toward said outlet.

11. In a fan as claimed in claim 1, said inlet and outlet making an angle of 45 with respect to each other.

12. In a fan asclaimed in claim 1, said second arcuate wall portion being cylindrical and having its axis eccentric to the axis of saidcylinders. v

13. In a fan as claimed in claim 12, said arcuate wall portion axis being located downstreamward with respect to the axis of said cylinders.

14. In a fan as claimed in claim 13, the radius of eurvature of said arcuate portion being less than the distance from the said arcuate portion to the axis of said cylinders. I 7

References Cited in the file of this patent UNITED STATES PATENTS 7 507,445 Mortier Oct. 24, 1893 

